Interactive horizon building, analysis and editing

ABSTRACT

A programmed computer-human interaction edit method and system for stored seismic horizon data where a two-dimensional graph of such primary horizon data is placed on a data tablet input to the programmed computer and wherein phantom horizon data with reference to coordinates of the graph are generated in response to human contact through the graph to the data tablet for direct input to the computer. Phantom horizon data is stored in a horizon segment file with primary segment data while preventing entry to the horizon segment file of horizon segment data beyond preselected constraints. Responsive to human contact through the graph to the data tablet at the location of phantom horizons and to stored horizon segment data, a first display of segments of two contiguous phantom horizons is produced with all constraint satisfying segments on the graph within a selectable time gate above and below both of the phantom horizons. A second display is produced of depthpoint-RMS velocity profiles for all segments on the first display. A third display is produced of depthpointinterval velocity data for the earth section between the horizons on the first display. Upon deletion of any segment from the first display, automatically and substantially simultaneously the second display and the third display are modified to reflect the removal of data corresponding to any deleted segment.

United States Patent Brittian et al.

[ May 6,1975

{ INTERACTIVE HORIZON BUILDING,

ANALYSIS AND EDITING {75] Inventors: Ronel W. Brittian, Dallas; Falvey L.

Malarcher, Plano; William A. Schneider, Dallas, all of Tex.

[73] Assignee: Texas Instruments Incorporated,

Dallas, Tex.

22 Filed; Dec. 30, 1971 21 Appl. N0.;214,14s

[52] U.S. C1. 340/155 DS; 178/18; 340/155 DP; 340/1725; 340/324 A; 340/365 R [51] Int. Cl G01v 1/28; G0lv 1/34; G06f 3/14 [58] Field of Search 444/1; 340/15, 15.5 DP, 340/155 DS, 324 A, 324 AD, 324 R, 172.5,

Primary Examiner-Harvey E. Springborn Assistant Examiner-Michael Sachs Attorney, Agent, or FirmHal Levine; Rene E. Grossman; Leo N. Heiting [57] ABSTRACT A programmed computer-human interaction edit method and system for stored seismic horizon data where a two-dimensional graph of such primary h0rizon data is placed on a data tablet input to the programmed computer and wherein phantom horizon data with reference to coordinates of the graph are generated in response to human contact through the graph to the data tablet for direct input to the computer. Phantom horizon data is stored in a horizon segment file with primary segment data while preventing entry to the horizon segment file of horizon segment data beyond preselected constraints. Responsive to human contact through the graph to the data tablet at the location of phantom horizons and to stored horizon segment data, a first display of segments of two contiguous phantom horizons is produced with all constraint satisfying segments on the graph within a selectable time gate above and below both of the phantom horizons. A second display is produced of depthpoint-RMS velocity profiles for all segments on the first display. A third display is produced of depthpoint-interval velocity data for the earth section between the horizons on the first display. Upon deletion of any segment from the first display, automatically and substantially simultaneously the second display and the third display are modified to reflect the removal of data corresponding to any deleted segment.

6 Claims, 32 Drawing Figures PATENTEBMAY BIBTS 3,882.446

SHEET G10? 13 PROSPECT GRID MAP 9 o FIG.

AMPLIFIER a RECORDER FIG. 2

(BOUND;

Pmimmm mm 3,882 .446

SIIEEI C 3 6F 13 HORIZON DEFINITION 1 PROSPECT TEXAS LINE 300 O BOTTOM I I 6/e "1-! .6 600 LAYER A PE 620- LAYER-C 63 I800 LAYER 63a 3000 LAYER'E LAYER-F 6000 L L 1 l I I 1 DEPTHPOINTS HORIZON EDIT PROSPECT PATHNAME LINE 308 500 I 37 73 I09 I45 I8! DEPTHPOINTS FIG. 5

HJENTED 51975 SHEET 5 GREEN 44d RMS AND INTERVAL VELOCITY DISPLAY FT/SEC IOSOO N m m w 0 0 H H H O O O O O O O 0 O 6 2 8 4 0 w 4 w 2 6 0 6 B 9 3 I 6 I 7 2 8 9 8 T T 69 a B 7 7 6 MS VELOC TY NTERVAL VELO T FIG. 8

/0/ -I PHANTOM TO 870A DISK J I /O2--|INPuT SEG. SUM FILE 1.D. I- @-IO3 0 I EXECUTE 870A TRANSFER I I L .IOAD H DIT 1- I05 I08 tASK FoR I-IoR. SE6. FILE 1-0-40? /09I GET FII E HEADER WORDS //0-LsET PARAMETER SPECS L SET VELOCITY SCALE l// V II2 KEY SEL? YES I I 1=I EY SELECTED 1/3 1/8 1/5 YES 69-43% I w IsPEcIFY INPuT DEvIcE G L ExITRTos 1 I I I360 @870 /22-I REo EDIT sTMT -)--I2I /23-{ PARAM INPUT J I26 No I29 a 6 O N 5? YES I27 I Gib I I EDIT INITIAI. 0.5. I ,1 L EDIT MAx D. P

lazfi I33 I36 I I L EDIT MIN TIME I I EDIT MAX TIME FIG. 9

IIIENTEDWIY sIsN 3.882.446

SHEET 0701 13 I REGISTER cooRDINATES @140 I F ROUND OFFCOORDINATES P I42 I43 DRAW GRID LINES JJ I DISPLAY ON SCREENS READ z HORIZONS }-l45 SCAN MIN 8 MAX $146 I F SET GRID SCREEN J- I47 l48 L DISPLAY GRID scREEN [59 F SET GRID SCREEN }--I49 I60 //50 NO REG. 0.I F DISPLAY GRID SCREEN J- YES SET GRID SCREEN }--/5/ TRACK To HARD COPY l DISPLAY :RID SCREEN REFRESH J-IGZ f PLOT ALL Iaz sEG i|i@ O START CURSOR 1/163 4 /I54 l PLOT ALL laz SEG. 96E

I I55 KEY SEL I PLOT ALL I a 2 AMP /I56 SUBROUTINE INTP T I PLOT INT vEI HI- 2 H 9 II I 1 SET REG 0. K. j-/5? 2 KEY=5 YES FTERMINATE SEG EDIT P166 I58 A FTuRN OFF REFRESH BUFF. P167 l I=KEY SELECTED FIG. IO

FAYENTEQBA. ssszs 3.882.446

SIIEET LBQF 13 1,75 @I74 I78 @177 I80 @179 TRACK DP-AMP j l TRACK DP-TIME J L TRACK [JP-VELOCITY L L I I84 @183 I87 @186 @H ZUBROUTINEMVERAGEJ I I ICLEAR DELETE FLAGS SuBRouTlf EflNTPLT) 1 @el SuaRouTIIiEmEPLoT; l@

I I I85 J 188 @1 SUBROUTINE(REPLOT) l-@ I AcTIvE SESMENTa F ZOOM 1 192 TWO TIMES INPUT AcTIvE SEGMENT YES L SET MAX-MIN TIME SET x-Y PRO. To SEGEDV L RESTORE TABLET PRO P196 FUNCTION KEY To SEGFKV P MCTWE SEGMENT L KEY sELEcTEo $210 I99 i eTRAcKINs IN TIME TERMINATE-RESTORE J-2// 2/2 L SET TABLET PROCESSING P200 NO KEY=3O YES 20] SEG FKT KEY SELECTED 202A TERMINATE I NO KEY=29 YES PAIENIEQII'AY 625. 5 3.882.446

SHEET 09 0F 13 NO 2 YES TIME MAPPING SET To HARD COPY ,2 HA D COPY T ME To DATA TABLET TIME To 2/5 R SCREEN 44 SCREEN 44 2/7 2I6-{ TURN KEY 3| LIGHT 0N TURN KEY 3| LIGHT OFF4}-2I8 VELOCITY DATA TABLET X-Y INPUT PROCESSOR FDR SEGI EDIT TIME MODE

TRACKING AMPLITuDI:

@4 MAP XY TO DP-VELOCITU MAP XY TO D.P. AMP.

I I F MAP XY TO D.P.-TIME ALL SEGMENTS IN HOR I 224 BI HOR 2 TO BE CHECKED V ACTUATE REFRESH BUFFER 7 OF CURSOR M I GB UNITS FIG. I2

[ MAP X-Y TO D.P. TIME P229 230 N0 IS D.P. W/I

ACTIVE SEG.

YES

[ ADJUST SAMPLE To TIME k23/ FIG. I3

233 MAP X-Y To D.R VELOCITY J 234 NO IS D.P. W/I

ACTIVE SEG YES 235 [ADJUST SAMPLE To vELocIT FIG. I4

PAIENIEQ HA! 5 SHEET 237- FORM ARRAY SUBROUTINE (GRID) I 238-UIVERAGE TIME I-IoR |2 a AVERAGE I-IoR I HOR 2 239-FHOR ME AT START OF. I A 240% HORIZON VELOCITY 252; PLOT TIME ARRAY AvE I- ALL DEPTHPOINTS I I 253I PLOT VEL ARRAY AvE J GDMPUTE HOR. vEL 254 24/ *(%IR) N0 ALL BLOCKS I PLOTTED? G0 L. YES

2 TZVI I z- I 255I SUBROUTINEUNT PLT) I-+@ 243 IV O 256$ RETURN TO CALL J 246 I 1v o 274 I DEFINE INT. VELOCITY J 2145 I ND. INT. vEL. I I PLDT a FDR IMAGE VJ l J GRID INT. VELOCITY 247 FROM MIN. MAX. 1v. 44d) I RETURN To CA L 266--F SCAN J I 267 N IS RANGE w/ 268 ZOOM RANGE' 1 YES I SET TO ZOOM RANGE 269I ERAsE scREENs 270-fi LoT GRID: D. P. TIME RETURN TO CALL FIG. 18

SUBROUTINE (GRID) YES 2 SEGDELE'IED.

260 No F PLOT D P. TIME PLOT D. P. VEL

. ALL SE6 5 PLOTTED YES 263% SUBROUTINEHNPLT) J-@ I 264 -I RETURN TO GALL I FIG. /7

T-s-JENTEW 61% 3,882,445;

SHEU 11B. 13

N0 ANY POINTS F SUBROUTlNEGAMPLEJ J 298 SAMPLED? 300 SET: No SAMPLING J BLOCK END POINT j lEocK END POINT- END I 293 1, 30/ 2940 SET: CONT. SAMPLE L SuBRouT|NE(TERB| K 294 F SUBROUTINE (SAMPLE) J FIG. 20

TL 306; INPUT! TIME NO 5 0 DP EDP a DP. NEw EDP 3/0 309 D.P. NEw EDP J I FILL ARRAYS J 3/! L SET: ALT HoR. DEF, 1 L j76 READJUST ARRAY J SET: No SEG'S= o 277 SET KEY: KGFK J (9 3 3 J, 278 1 0 VELOCITY FOR AVERAGE j I l [279 L coMPuTE A vELoclTYJ YES 3/4 REFRESH I I J l SET VELOCITY J 3l5 @(JCLEAR REFRESH a REPLOT J i1 23 1 RETURN To CALL J---3I6 WHERE l=KEY o T F SUBROUTINE (TERBLK) J 2884 RESET 1 No 289 290 ANY BLOCKS DEFINED? YES FIG. I9 Q 29/ K SET: DEFINE NEXT BLOCK P318 INCREMENT 3/9 I I. DEFINED? L RETURN TO cALL P320 FIG. 22

SUFFICIENT CORE FOR DEFINITION AcTIvE HORIZON AVERAGE K6XY 32/ OF EACH BLOCK I MAP x Y To J'razz 332-{ START REFRESH BUFFER POSITION cURSoR T323 333 I SET KTFK 8 K7) I 324 CONTINUOUS No SAMPLING ON? YES 3 LSUBROUTINE (SAMPLE) J-3Z6 336 3 5 KEY I61 327 L RESET NO 338 I TURN oFF REFRESH BUFFER I I6,I7 KEY=I6 T SET=CONTINUOUS SAMPLING J 339 -EET NOT CONTI \IUOUS SAMPL. J

343 SUBROUTINE (ADJVEL) P34! FIG. 24

DP SAMPLE W/i ANY HORIZON BLOCK ACTIVE? YES L ADJUST VELOCITY k345 @e-L ADJUST REFRESH BUFFER 1- 346- l RETURN TO cALL P347 349 MAP x Y To DP VEL J 350L POSITION cURSoR w CONT SAMPLING 0N YES I SUBRDUTINE (ADJVEL) f 52 KYFK P JENIEU HA! 6 i975 SHEET 354 (9 1% 386 f INPUT AMP aouNDs j YES HOR I DATA BASE 356 387-{ DELETE SEGMENTS J l sET HOR 2 AcTIvE 357 f )-388 355 I PLOT HOR I J I PLOT INT. VEL J--*@ F SECTION ENDED J MAKE HOR 2 HORI I l J 369 I REINITIAUIZATION I FsET NoT HOR 2 IN CORE J i I MAKE HORZ HORI J 4 N0 2 ANY MORE HORIZONS? YES HOR'ZONS? YES Jg BRING IN NEXT HORZ I SUBROUTINE (GRID) I L SUBROUTIN SET DELETE ANNATOTE GRIDS FIG. 30

E (REPLOT) FIG. 27

ran

INTERACTIVE HORIZON BUILDING, ANALYSIS AND EDITING This invention relates to computer-human interactive construction of a reliable seismic horizon data base, and more particularly to an interactive method of machine processing seismic data.

A seismic prospect normally is worked by selecting lines along which seismic shooting operations are to be performed. Traverses laid out in a grid permit analysis of subsurface horizons in closed loops. Thus, as in surface contour surveying practices. elevations around a loop may be tied back to the starting point. Accuracy of the elevations at all points around the loop is confirmed by loop closure.

In accordance with US. Pat. No. 2,732,906 to Mayne. common depthpoint seismic surveying provides for a statistical improvement of the raw seismic data. In common depthpoint seismic surveying, seismic signals reflected from a common subsurface reflecting point and detected after travel over many different paths are corrected for differences in geometry of the travel paths. i.e.. normal movement. The signals are then combined or summed to provide a single tract which statistically represents the composite reflection of seismic energy traveling over the several paths to and from the common reflection point. When such operations are carried out over traverses of significant length. a seismic section may be produced which in essence is a graph of the amplitude of the composite common depthpoint reflections as a function of seismic record time. Such time-amplitude sections may be pres ented in several different modes. The modes have come to be referred to as wiggle trace. variable area. variable density and the like.

Having produced such a seismic section for a given traverse, an interpreter may view the section graph and observe coherence across the graph between adjacent traces. Such coherence may appear at various time points down the graph. Coherent high amplitude portions of the traces may be referred to as seismic segments which if real and properly related to velocity at which the seismic energy traveled, indicates the depth of the seismic reflector in the earth. The presence of well defined continuous horizontal subsurface reflecting horizons under a constant velocity overburden ap pears on a seismic record section as horizontal lines. Such lines on a seismic section are formed by high amplitude signals being substantially in phase across an entire record section.

The volume of seismic data embodied in a seismic record section can become astronomical. This is readily apparent when it is considered that seismic waves may be detected at points on the earths surface spaced about I feet apart over a traverse of ten to twenty miles in length. For each depthpoint there will be added together as many as 24 seismic traces to form a single trace on a seismic record section. The traces each will be digitized with time samples taken at intervals of the order of from 0.001 to 0.004 seconds.

The present invention is concerned with the utilization of automatic data processing systems with human intervention. and particularly to a phase of such processing techniques which are carried out after segments have been identified.

Common dcpthpoint seismic data will be used herein by way of example. but other types of data may also be processed Preferably, data defining seismic segments will be of the type produced by Geophysical Services. Inc. of Dallas. Texas. a subsidiary of Texas Instruments Incorporated. through use of the methods sold and used under the name 600 Package" and 700 Package." the former being described in a bulletin entitled 600 Package" dated July 1970. Such data is stored in retrievable form in computer storage. For the purpose of the present invention, it will be assumed that a segment summary file exists for individual space gates into which a given seismic traverse may be divided. The segment data in a segment summary file for each space gate may then be stored and retrieved as a unit for further refinement and processing.

Seismic segments appearing on a given seismic section graph will be identified by said 600 Package" process or may otherwise be cataloged in accordance with the following table.

TABLE I Summary File Entries WORD SYMBOL DESCRIPTION n [DE Segment number (sequence ordered in depthpoint/time.)

n+l DPR Initial depthpoint of segment upper '9 hits. number of depthpoints lower 9 bits.

n+2 A, Time (ms) of the segment at the reference depthpoint.

n+3 A, Gradient (l).l ms/dp] of segment at reference depthpoint.

n+4 A, Second derivative of time of segment at reference depthpoint (0.0l ms).

n+5 MA. Local mean amplitude of segment from IDP (initial depthpointl to FDP [final depthpoint l.

n+6 MM, Local mean moveout of segment from IDP to FDP.

The data appearing in Table l preferably is further distilled in accordance with operations described and claimed in Interactive Multidimensional Classification and Sorting of Seismic Segment Data". Ser. No. 2I4,l88. filed Dec. 30. I97] and Method and System For The Interactive Determination of Subsurface Velocity From Seismic Segment Data. Ser. No. 214.]89. Filed Dec. 30. l97l.

In accordance with the present invention. a programmed computer-human interaction edit method is provided for seismic horizon data base stored with a seismic section summary file. A two-dimensional graph of such seismic data is employed. Phantom horizon data are generated with reference to coordinates of the graph in response to human operation on the graph for direct input to the processor. The invention comprises storing the phantom horizon data with seismic section summary file data in retrievable form in a horizon segment file while preventing entry to the horizon segment file of summary file data which are outside preselected constraints. In response to horizon segment file data. a first display is produced of two contiguous phantom horizons along with all constraint satisfying primary seismic segments on the graph within a selectable time gate above and below the phantom horizons. A second dis play is produced ofthe RMS velocities for all segments on the first display. A third display is produced of the interval velocity for the seismic section between the horizons on the first display. Upon deletion or alteration of any segment from the first display. automatically and substantially simultaneously the second display of RMS velocity and the third display of interval velocity are modified to reflect the change. Data representing the operators designation of a reflector at a location within the constraints is then stored and/or displayed.

It should be appreciated that although the invention has been characterized as comprising four individual display screens, another possible embodiment which does not depart from the sprit of the present invention is the use ofa single display screen having four discrete display areas thereon.

For a more complete understanding of the present invention and for further objects and advantages thereof, reference may now be had to the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a typical prospect grid map illustrated in plan view;

FIG, 2 is a schematic representation of a portion of the grid map of FIG. I illustrating common depthpoint operations and identifying and defining depthpoint as used herein;

FIG. 3 is a perspective view ofa computer-human interaction system employed in carrying out the present invention;

FIG. 4 illustrates selection of horizon and dilineators as may be carried out by an operator in the system of FIG. 3'.

FIG. 5 illustrates a display of two contiguous phantom horizons and stored seismic segment data which satisfies predetermined constraints and which lie within predetermined time gates relative to the two phantom horizons;

FIG. 6 illustrates a display employed in accordance with the present invention which illustrates a display after having selected a first horizon as being a true hori zon;

FIG. 7 illustrates a display of RMS and interval velocities as produced in the system of FIG. 1 for use by an operator;

FIG. 8 illustrates a modification of the display of FIG. 7 in the course ofoperations carried out in accordance with the present invention;

FIG 9 is a flow chart illustrating a portion of the operations carried out in editing a horizon segment file and is related to operations instigated by an operator through unit 36, FIG. 3, wherein a keyboard having keys 0-31 are available to select different operations;

FIG. 10 illustrates a continuation of the flow chart of FIG. 9 showing operations in response to actuations of keys K4 and K5;

FIG. I 1 illustrates the flow charts for operations initiated by actuation of keys K5(l6). K5(I7]. K5(l8),

FIG. is a flow chart illustrating operations initiated by actuation of keys K6( [6), (17), (24);

FIG. 21 is a flow chart illustrating a subroutine SAM- PLE;

FIG. 22 is a flow chart illustrating a subroutine 'I'ERBLK;

FIG. 23 is a flow chart illustrating operations initiated by depressing key K6 and entering X-Y via a keyboard;

FIG. 24 is a flow chart illustrating operations initiated by depressing key K7;

FIG. 25 is a flow chart illustrating the subroutine ADJVEL;

FIG. 26 is a flow chart initiated by depressing key K7 and entering X-Y through the teletype;

FIG. 27 is a flow chart illustrating operations initiated by depressing key K8;

FIG. 28 is a flow chart illustrating operations initiated by depressing key K10;

FIG. 29 is a flow chart illustrating operations initiated by depressing key Kll;

FIG. 30 is a flow chart illustrating operations initiated by depressing key K12;

FIG. 31 is a flow chart illustrating operation by depressing key Kl3; and

FIG. 32 is a flow chart illustrating operation by depressing key K25.

Referring now to FIG. I, a plan view of a seismic exploration prospect is shown. The prospect may be of the order of twenty miles square. Six seismic traverses are designated. Traverses [-6 are lines along which seismic exploration will be conducted to provide seismic data. preferably common depthpoint data of the type generally disclosed in US. Pat. No. 2,732,906 to Mayne. Further, the seismic data preferably will be re corded digitally as is well known in the art, the recordings being in reproducible form for storage in an automatic data processing system.

In FIG. 2, line I of the prospect has been illustrated wherein shot points 10, I], I2 and 13 form a portion of a series of shot points along line I with geophones 14 positioned at uniform spacings along line I for detection of seismic energy. Common depthpoint stacking procedures involve combining signals such as generated by geophone 15 of energy from shot point II with signals from geophone [6 of seismic energy generated at shot point 10. A common reflecting point I7 lies on a reflecting horizon l8.

For the purpose of the present invention, the term depthpoints will be employed to refer to the surface location of a line 19 which contains subsurface reflection points such as point I7. Thus, from operations based upon the geometry illustrated in FIG. 2, there would be data generated for depthpoints corresponding with the location of each of the geophones along line I and also for depthpoints located midway between each of the geophones along line I.

By detonating the explosive at shot point I0 and detecting the same at a given set of detectors along line I, there may be produced a normal wiggle trace seismogram 24 which has the instant of detonation of the explosive sealed at zero time and with the time of travel to a reflecting point and back to the earths surface scaled along the length of the record.

In idealized form, two reflections have been illustrated on record 24. A first reflection 20 which occurs at about 1.0 second on the record and the second reflection 2] that occurs at about 1.75 seconds. Because of the presence of noise. multiple reflections and the like, seismic record sections may contain many false reflections (not shown) along with true reflections.

In accordance with prior art techniques. the individual traces in digitized form are analyzed to identify seismic segments identified as set out in Table I above.

In FIG. 2, it will be noted that there is coherence in reflection in that all of the troughs occur along the dotted line 22. Similarly, dotted line 23 represents a time pick of the lineup of the troughs in reflection 21. Similar lines may be plotted for peak segments. On the simplified seismogram of FIG. 2, time-depthpoint data representing lines 22 and 23 would form what will be referred to herein as primary seismic segments.

For a seismic record section the data from which is stored in memory in the form of Table I. each seismic segment is identified by a segment number. In carrying out the present invention, depthpoints are selected along the traverse. not at the frequent intervals illustrated in FIG. 2, but at depthpoints which occur at the order of three or four points per mile. For each such depthpoint. the seismic segments encountered will be stored as in Table I. At the same time. a seismic section which is a graph of line 1 is produced and used herein. Two main sets of data are employed in the present invention: (I segment data stored in the format ofTable I and (2) a corresponding seismic record section.

The present invention provides for a refinement of the record section to eliminate extraneous unwanted. unreal or erroneous seismic segments and to provide an ultimate section which is more reliable.

Major steps are as follows:

1. lnteractively input a phantom horizon or delineator such as a fault consisting of (depthpoint. time) pairs via the digital data tablet.

2. Select segment data within a specified threshold about the phantom horizon on the basis of time. RMS velocity and amplitude.

3. Display the selected segment data to an operator on a storage tube display system to permit the user interactively to analyze and edit the segment data in order to add the velocity attribute to the subsurface model.

Conventional processing to accomplish the same goal is a laborious task involving manual segment selection and is available only in a batch processing environment. Cost and time prohibit the construction of a detailed subsurface model using conventional methods.

Thus. important features of the present method are:

l. lnteractively to analyze and edit segment data and observe the perturbation on RMS and interval velocity in a real-time environment.

2. Optionally to honor the segment data or to provide an RMS velocity function of the operators choice via an interactive input in the form of a data tablet with similar capability for the operator to override the time attribute of the selected segment data.

3. To define and edit horizons with a visual display of horizon information.

4. To obtain a subsurface model with a higher confidence level in less time.

FIG. 3 illustrates basic system components employed herein. An operator who is to interpret seismic data faces a plurality of instruments. Included are.

a conventional keyboard machine 32 which has a vi sual readout screen 34;

a function key set 36 which includes a plurality of function keys 38 which may be manually depressed by operator 30 to initiate automatic performance of functions to be later described;

a reproducing machine 40 interconnected with the system to provide hard copies of displays selected by operator 30;

a monitor 42 which includes four storage tube display screens 44u-44d upon which are displayed various functions during the operation of the system; and

a data responsive surface 46 disposed on the table in front of the operator 30 over which a seismic section 48 may be placed.

The seismic section 48 graphically corresponds with the source of the data set to be interpreted and is an object upon which operations are performed. Graph 48 has as time ordinates and depthpoint locations as abscissae. A plurality of space gates taken along a seismic survey line may be encompassed by graph 48. Such graphs are commonly termed VAR sections which are variable area type of seismic signal presentations.

The data responsive surface 46 comprises a flat insulating sheet or plate overlaying a network of X-Y conductors. not shown. A stylus 50 connected by an elec' tric cable 52 is held by operator 30 and is moved adjacent the location of selected points on graph 48 to initiate selected displays upon the display unit 42. Stylus 50 senses electric fields generated by the network of conductors. In one mode. circuitry associated with stylus 50 and data responsive surface 46 generates electrical signals representative of the position of stylus 50 relative to graph 48. The path of the stylus may be made immediately to appear on one of the displays 4411-4411 in true relation to the coordinates on graph 48. In general. the capability of writing on a screen in real time in response to movement of a stylus over a data tablet is well known.

An automatic data processor 54 is interconnected with the various components of the system illustrated in FIG. 3 uniquely to interact with operator 30 to provide desired displays of seismic data upon the display screens 4411-4411.

In a preferred embodiment, the computer 54 comprises a SEL 810A computer manufactured and sold by Systems Engineering Laboratories of Fort Lauderdale. Florida. In order to supply needed storage and processing capability. an 870A TIAC computer manufactured by Texas Instruments Incorporated of Dallas. Texas is utilized in tandem with the SEL 810A. The 870A is described in TIAC Model 870A Programmers Reference Manual, Texas Instruments Incorporated. I968. However. other general purpose digital computers could be utilized.

A suitable keyboard 32 for use with the invention is manufactured and sold by Computek. Inc. of Cambridge. Massachusetts and identified as 400 CRT Display System.

A suitable reproducing machine 40 is Model 460I, manufactured and sold by Tektronik. Inc. of Portland. Oregon.

Display units 44u44a comprise a Computek Model 430. Information relative to the formation of output display buffers for use with the display system is found in the Users Manual Series 400 CRT Display System. Bulletin 400M. published July. 1969. by Computek. Inc. of I43 Albany Street. Cambridge. Massachusetts.

A data responsive table 46 suitable for use with the invention comprises a system heretofore manufactured by Bolt. Beranek & Newman. Inc.. Data Equipment Division, Santa Ana. California and now manufactured by Compunetics of Monroeville, Pennsylvania. A suitable tablet 26 is identified as Model 2020 Data Tablet".

Preparatory to carrying out the present method. computer 54 receives and stores segment data for one or more space gates. the data being in the form designated in Table l. Computer 54 also stores therein instructions to operate upon the stored segment data. Horizon segment data will be then displayed upon screen 44a as designated by operator 30. Operator 30 may actuate a function key in set 36 selectively to vary any portion of the displays on screens 440-44d. By operation of the reproducing machine 40, the operator 30 may produce permanent records of the results of operation of the system.

Operation in accordance with the invention is initiated by the operator 30 by positioning the graph 48 upon the data responsive surface 46 and by setting up the system for operation by the use of the keyboard 32. As previously noted. the graph 48 preferably comprises a common depthpoint stack section or graph having time-depthpoint coordinates divided up into a plurality of space gates and for which the Table I data has been stored in computer 54.

Horizon Definition Phase In a horizon definition phase, operator 30 generates phantom horizon data. This is done by tracing a line with stylus 50 across the graph 48. The line is one which. in the opinion of operator 30. corresponds with the most likely location of a reflecting horizon. Such choice is made from the operator's visual inspection of and judgment relative to graph 48. Operator 30 sets the system so that on one ofthe screens 44a-44d there will be presented a scaled representation of the phantom horizon traced by operator 30. More particularly, as shown in FIG. 4, operator 30 would cause screen 44c to provide a presentation wherein time is scaled along the vertical border and the locations of depthpoints scaled along the bottom horizontal border, in replication of part of the scale on graph 48.

Operator 30 may then select a number of zones in which he concludes that a reflecting horizon is present. FIG. 4 illustrates phantom layers 61-66 chosen by operator 30. Layer 6l has a block 61:: which does not directly die with a second block b. Breaks in time are also identified between 61a and 610. A break also separates blocks 61c and 61f In a similar manner. the oper ator traces with stylus 50 blocks 62u62e of layer 62. Blocks 63a-63d comprise layer 63. Blocks 640-64d comprise layer 64. Layers 65 and 66 are considered by operator 30 to be continuous unbroken blocks. Operator 30, based upon such interpretation of the graph 48, may then trace paths which he postulates are delinea tors which represent faulting.

In FIG. 4 five faults 67-71 have been postulated by operator 30. Data representing faults 67-71 produced in the initial operation are stored. More particularly. lines representing faults 67-71 are traced by stylus 50 and as they are so traced. the system generates and stores in retrievable form sets of data representing the lines themselves so that in response to computer operation when called upon. the delineator can be retraced for display or for printing. Such delinerators will be named. i.e.. given a code number and the time depthpoint data will be stored. The same is true as to the data representing layers 61-66. As they are traced. representative timedepthpoint data are stored in the computer 54 along with a given code number.

The main purpose in this phase of the interactive ho rizon building system is to enable the user to enter phantom horizons and delinerators into the horizon data base. The main input is an interpreted seismic section; the main output is an updated horizon data base containing phantom horizons and/or delineators.

Operator 30 will process one section of a line at a time; the program can be executed several times to process multiple sections or lines. All horizons and delineators entered for a given section are maintained in computer 54 memory. Operator 30 may delete and redraw or add new horizons and delineators without committing the information to the horizon data base until he has the structure in the section defined exactly as he chooses. At any time during this phase, operator 30 may depress a function key to select a Horizon Extension option. If he does so, when any grid is redrawn, information is extracted from the horizon data base about existing horizons and delineators in the section. This information is put into the form of a display file which is then read and plotted on the appropriate one of screens 44a-44d.

When operator 30 finishes processing a section of a line. the phantom horizon and delineator information is sent to the 870A disk as a phantom file which is then added to the current horizon data base.

HORIZON EDIT PHASE In a horizon edit phase. a set of working displays are provided on screens 44u-44d. More particularly. FIG. 5 illustrates a display which will be presented on screen 44c. FIG. 5 is representation having an enlarged time scale of portions of the phantom horizons 61 and 62, as drawn by operator 30. Also shown are all of the primary segments stored in a memory within predetermined thresholds about the layers 6] and 62. More particularly. upper phantom horizon 61 is at a time of about 680 milliseconds. All primary seismic segments lying within ilOO milliseconds of horizon 6] are dis played. Similarly. the second phantom horizon 62, FIG. 5, appears at about I260 milliseconds with all of the primary segments displayed which lie within 150 milli seconds of layer 62.

FIG. 6 illustrates an accumulation display. On screen 44!). a grid is presented upon which data ultimately satisfactory to 30 will be displayed.

Screen 44d will display data forming two graphs shown in FIG. 7. The first graph is an RMS velocity graph for each of the segments displayed in FIG. 5. The second graph 76 portrays the interval velocity. namely the velocity over the vertical section of formations between the horizons 61 and 62.

FIG. 8 illustrates a modification of the data shown in FIG. 7. The modification is achieved in the course of the edit process as will later be described.

Screen 44a. FIG. 3, will provide a display of the amplitudes of the seismic signals comprising each of the seismic segments. Horizon l amplitudes will be plotted across the top half of the screen. Horizon 2 amplitudes will be plotted across the bottom half.

Thus. the operator has presented to him on screens 4404411 all of the primary seismic segments lying within predetermined thresholds about each of two contiguous phantom horizons, together with RMS velocities for the various primary segments and for the interval therebetween, respectively, and a portrayal of the amplitude of all primary seismic segments.

The display computer system is programmed to respond to operator 30 through stylus 50 and through the key set 36 to manipulate the data appearing on screens 44a44d for the selection and editing of horizons to form a subsurface model with a higher confidence level than has heretofore been possible. This is made possible by operation of the interactive programmed computer-human linkage in such a manner to provide real time displays of any changes desired with the possibility of rewriting and reworking the data at the will of operator 30.

In the edit phase. the purpose is to integrate segment information from a horizon segment file into the sub surface model. Section summary files covering the area of interest are resident on the disk at the time this phase of the processing is entered. The main output is an updated horizon data base which contains true" horizons as replacements for phantoms; the true horizons will have a space-varying RMS velocity attribute associated with them. They will be accumulated and displayed on screen 44!).

Operator 30 specifies all parameters used in picking segments about horizons. The names of the horizons in the order to be edited must be specified as well as the name of the input section summary file to be used. plus the name of the output horizon segment file to be used. Operator 30 may either name a phantom file to use as input or may indicate that the horizon data base is to be used. In the latter case. a temporary phantom file with the same spatial extent as the input section summary file is extracted from the horizon data base.

The operator 30 calls for selection of segments within specified thresholds about horizons. The main input is a phantom file and a section summary file; the main output is a horizon segment file which contains all of the selected segments in the section of interest. When the first part (two horizons) of a horizon segment file have been input. the horizon edit process can begin.

In the horizon edit process. operator 30 analyzes and edits the segment data about each horizon. He can selectively delete segments and observe the time and RMS velocity averages of the remaining segments. He can select one segment to represent the true" horizon. Alternatively. if he chooses. he can draw in the time and/or RMS velocity of the horizon in question. During the horizon edit process. operator 30 can select the "horizon extension" option just as he could in the horizon definition process. By depressing the appropriate function key. operator 30 can set a mode whereby a program reconstructs a current data display whenever grids are redrawn. The latter program may provide the horizon extension file for use in the horizon edit pro cess with the horizon extension information available on two screens 44c and 44d.

When operator 30 finishes editing a given horizon, the horizon file is sent to the 870A disk for storage. Phantom horizons in the horizon data base are then re placed with the true" horizons contained in the horizon file.

Certain segments in the original input section summary file will be flagged. Segments selected about the phantom as well as segments (if any) contributing to the "true" horizon will be marked with special flags.

The flags can then be used to obtain various segment displays which. in conjunction with section displays from the horizon data base. will provide a hard copy re cord of the horizon edit process.

The edit process is repeated for each horizon in the section of interest.

Operations under control of operator 30 are carried out by his generation of input data through the use of stylus 30 as above described and his manipulation of the function keys in the unit 36.

The functions that may be selected are as set out in B Table II.

TABLE II Function TABLE III HORIZON SEGMENT FILE FORMAT Word Description I28 Pathnames (Prospect. Type. Phase.

Line. Range. Version. File) 29 Min. Dp 30 Max. Dp 3l Min. Time MS. fig 32 Max. Time MS. 33 Min. RMS Velocity FT/SEC'. 34 Max. RMS Velocity F'T/SEC. 35 No. of Gates N 36 DP of Gate (enter Gate l 36+: No. Horizons K 37+N Word offset to first Hori/on 37+k+| No. Words in HSF h 3X+N+K L'NlT SWITCH l ll't Last Word of HSF header TABLE IV HORIZON SECTION OF FILE TABLE V-Continued Key or p No. Symbol Function 1-4 Horizon Name 5 I I2 8 I awaits action by operator proceed BLOCKS B from this point by operator activating 6 No. Segments Block I function key. 'I I0 End Point Classification Start Block I I [3 When operator depresses function key. I End ClflSfilflCflllO" the identity of the key is stored and End Block I identified as I. I5 No. Segments Block 2 [U I I4 Check to see if key selected is acceptable,

i.e. o l I 3.

6+9B Segment ID I I Ktl) Any key (I) between 0 and 5 may now be 7+9B SDP Start Depthpotnt selected by operator 30. 8+9B EDP End Depthpoint 9+9B No. Words this segment H I I6 K10) Operator depresses KtO). IO-i-JB Time at SDP I I7 Screen 34 displays a list of data required to be specified by operator 30 9+9B+J Time at EDP to select the device he wishes to use l0+9B+J Velocity at SDP as a system input (SI) device.

9+9B+2J v I I P e Om) M ED I8 Display I I7 is formed. H9344; Ampmude m SDP I I9 System returns to state ready for entry 9+ m+3r Amplitude at EDP m+g8+3j Segmem [D 120 K( I Operator depresses Kl I I to initiate conditions permitting operator 30 to edit With the data thus present in the horizon segment the pummeerb' file. the edit operation may then proceed under the I2! Disptayon screen 34 lists parameters to control of operator with the capability of the combe requred by puter marshalled and available to carry out the opera I22 Forms parameter edit statement request tion indicated in Table V. The edit operation detailed in Table V begins with information from the section g h parameter desired specified by number summary file and from the phantom file available. Such 30 P l parameter wlll have the number n, where information 15 called in response to steps identified as 0 n 5 ste I00 et se O erator 30 initiall de resses ke I lmcrmgme See Specified i5 f 36 p h p y greater than Oand less than 5. If I24 0 umt to Inmate t e e It p is false. system to return to operating state A, FIG. 9,

TABLE V 125 If I24 is true. then the operator may edit the parameter called for in step I23.

y m I26 Enter an edit function. where n=l, from No. Symbol Function step I25.

I00 KM) Initiate transfer of phantom file from I27 Operator 30 edits initial depthpoint.

810 storage to 8702 disk storage.

I 28 System returns to state for K( I I operation 101 Execute transfer of step I00. after editing initial depthpoint.

I02 Orperator specifies via keyboard the portion [2) n= 2. step I25.

0 section summary file required for edit use. I30 Operator 30 edits the maximum depthpoint.

I03 Screen display of list of data required I3l Same as I28.

to be specified by operator 30 to specifiy step I02 disply on screen 34. I32 n=3. step I25. I04 Horizon segment file is formed by execution I33 Operator 30 edits the minimum time.

of 870A program on designated segment summary file data and phantom I34 Same file data with phantom horizons sorted on basis of time of occurrence in the D section. i.e.. from min. time to max. time. I36 Operator 30 edlls 1h? mwflmum llmcv I05 Load horizon edit program (HEDITJ in BIO same terminal to be ready for execution of edit operation. I35a K(3) Operator 30 depresses K( 3]. I06 K(2) Operator may depress key 2. unit 36, to I353 lhis link restart the link between the horizon definition y phase and hmimn ed h I37a Exit to terminate operation at whateter point operator 30 has reached. I07 Screen 34 display lists operator input necessary to specify horiyon segment file. I39 006F111"! pr e N I- ma Fmms displayuf Smp 7 [40 Display formed on screen 34 tahulating information required of operator 30 to I09 Transfer first I28 header words (Table "P Y m m III) from 870A disk m 810 core. tablet b) y vs- H dsplh t"! (DPI) and initial time (TIMI). (-I initial I I0 Set parameters now in core to a file 05 FP P lDPl l "ndmuxlmum suitable for screen presentations. I'IMX and (fl) mu p p (DPXI and maximum tlme ITIMX I.

l I I Set velocity scale in response to unit- I4I hxecute step 140.

switch (foot-meters) parameters of Table III. 

1. A seismic data selective display system comprising: a data tablet having a surface for receiving a two dimensional graph of primary horizon segment data and including a stylus movable relative to said surface for generating electrical signals representative of a desired location of horizon data on said two dimensional graph, means for storing electrical representations of said horizon segment data including means for generating electrical position signals representative of selected portions of said horizon segment data, first display means responsive to said electrical position signals for displaying horizon segment data including means responsive to said electrical signals generated by said stylus for displaying lines traced by movement of said stylus over said two dimensional graph and said data tablet surface, and a function key box interconnected to said display means which includes a plurality of switches for controlling the selection of portions of the displayed horizon segment data.
 2. The system of claim 1 and further comprising: second display means for displaying a depth point-RMS velocity profile for all displayed horizon segments.
 3. The system of claim 2 and further comprising: third display means for displaying depth point-interval velocity data for the earth section between the displayed horizon segments.
 4. The system of claim 2 and further comprising: additional means for storing in retrievable form phantom horizon data generated by movement of said stylus across said data tablet including means for storing only portions of said selected horizon segment data.
 5. A seismic data selective display system comprising: a data tablet having a surface for receiving a two dimensional graph of primary horizon segment data and including a stylus movable relative to said surface for generating electrical signals representative of a desired location of a horizon data on said two dimensional graph, means for storing electrical representations of said horizon segment data including means for generating electrical position signals representative of selected portions of said horizon segment data, first display means responsive to said electrical position signals for displaying horizon segment data including means responsive to said electrical signals generated by said stylus for displaying lines traced by movement of said stylus over said two dimensional graph and said data tablet surface, a function key box interconnected to said display means which includes a plurality of switches for the selection of portions of the displayed horizon segment data, second display means for displaying a depth point-RMS velocity profile for all horizon segments on said first display means, third display means for displaying depth point-interval velocity data for the earth section between the horizons on said first display means, operative means connected to said second and third display means for reflecting the deletion of data corresponding to the nonselected horizon segment data.
 6. The system of claim 5 and further comprising: additional means for storing in retrievable form phantom horizon data generated by movement of said stylus across said data tablet including means for storing only portions of said selected horizon segment, and fourth display means for displaying said selected stored horizon segment data. 